1. Field of the Invention
The present invention relates to a bonding apparatus.
2. Prior Art
Several different kinds of bonding apparatuses are conventionally known. Among them, there is a bonding apparatus that has a cam and a motor that rotates both ways. The cam moves a capillary down when the motor rotates forward, and the cam moves the capillary up when the motor rotates in reverse.
In general, when the power of the bonding apparatus is turned on, a holding current or voltage is applied to a motor which moves a capillary and the output shaft of the motor is held so as not to be rotated. When a plus or minus current or a predetermined amount of voltage is applied to the motor, the output shaft of the motor is rotated.
As for the bonding apparatus in which the capillary is descended when the cam is rotated as described above, the holding of the output shaft of the motor is loosened when the power of the bonding apparatus is intentionally or unintentionally turned off. As a result, a cam shaft connected to the output shaft of the motor can be rotated freely.
In case that the cam shaft becomes free to rotate due to the power being off, the cam tends to rotate in a direction which moves the capillary so that it contacts a sample or a sample stand, resulting in a capillary that is damaged or a sample that is scratched because the capillary contacts the sample, etc,.